水溶液中不同氨基酸与甲醇分子间的异系焓相互作用

目的 探讨氨基酸-甲醇-水三元体系中溶质分子间相互作用机制，为揭示蛋白质的稳定机制、蛋白质变性的原因和生物大分子与小分子间的相互作用提供溶液热力学依据。方法利用2277热活性检测仪的流动测量系统测定298．15K时甘氨酸、丝氨酸、脯氨酸分别与甲醇在水溶液中的混合过程的热功率和稀释热功率，依据McMillan-Mayer理论进行多元线性回归分析。结果得到氨基酸和甲醇相互作用的混合焓以及各自的稀释焓和异系焓相互作用系数。利用k值讨论了不同氨基酸与甲醇分子的作用机制。结论不同氨基酸与甲醇分子间的焓作用系数的大小主要取决于氨基酸分子结构的差异，氨基酸的非极性侧基对焓作用系数有正贡献；脯氨酸特殊的五元吡咯环结构也表现出疏水性，对hxy值有较大的正贡献。

Heterotactic enthalpic interaction between different amino acids and methanol in aqueous solutions at 298.15 K

Objective: To obtain the information about solute solvation and solute interactions in aqueous media, and a better understanding of their role in the conformational stability and unfolding behavior of proteins. Methods: Heat power of mixing and dilution of aqueous methanol solutions and aqueous amino acids (glycine, serine,proline) solutions were determined at 298.15K by 2277 Thermal Activity Monitor of flow microcalorimetric system, and the data were analyzed according to the McMillan-Mayer theory. Results: Enthalpies of dilution and mixing of aqueous amino acid solution and aqueous methanol and the enthalpic interaction coefficients were obtained. The action mechanism of different amino acids and methanol molecules was discussed. Conclusion: The h xy values between amino acids and the methanol are contingent on the discrepancies of the structure of amino acids. The different side-groups of amino acids has positive contribution to h xy .